1. Field of the Invention
The present invention relates to an encryption control apparatus for encrypting and decrypting data.
2. Description of the Related Art
With the recent development of communication techniques, data having the same value as notes, such as electronic money, has been used increasingly, and it becomes quite important to prevent illegal leakage of the data or unauthorized tampering with the data.
As one of the safety measures to protect data, a data encryption and decryption technique has been used, by which data is encrypted when being sent and the receive data is decrypted at the receiver's end. General information processing devices, such as personal computers (hereinafter, abbreviated to PCs occasionally), have been used in encrypting and decrypting data.
Incidentally, attention has been paid to a system that employs an IC card as a typical example of a system capable of dealing with electronic money, etc, and an I/O control unit composed of a plurality of semiconductor devices has been used as an I/O control unit for controlling peripherals, such as an IC card reader/writer that accesses the IC card.
However, when an encryption/decryption computation is carried out by a general information processing device, it is difficult to conceal an encryption/decryption algorithm or a key used in encrypting/decrypting data. Therefore, such an algorithm or a key may be leaked illegally, resulting in unauthorized tampering with the data.
Also, because the conventional I/O control unit for controlling the peripherals, such as the IC card reader/writer, is composed of a plurality of semiconductor devices, progress information of the I/O control job is outputted to an address bus or a data bus interconnecting the semiconductor devices, thereby exposing such information to the risk of stealing.
As has been discussed, the conventional technique poses a problem in data security, and there has been an increasing need to ensure the security.